A. Field of the Invention
The present invention relates to a chain of the kind used for transmission and/or transportation.
B. Description of the Related Art
A conventional roller and bush chain used for transmission or transportation purposes has pairs of opposed inner link plates that are interconnected with opposed pairs of outer link plates by pins about which the inner link plates articulate. Each pin is fixed at each end to an outer link plate but is pivotal relative to the inner link plates within a bush that extends between opposed apertures in the inner link plates.
Our co-pending PCT patent application WO 98/26199 describes a chain in which the outer link plates are mounted pivotally on the pin and a bearing is defined between the pin and the outer link plate. In one particular embodiment of WO98/26199 (FIGS. 14 to 16) the ends of each pin carry a bush on which the outer link plate articulates. The bush has a radially projecting lobe and the aperture of outer link plate has a corresponding recessed portion. In order to assemble the chain, the recess and the lobe are aligned and the outer link plate is moved axially with respect to the pin so that the recess passes over the lobe. When the outer link plate has passed clear of the lobe it is rotated through 90 degrees into longitudinal alignment with the other link plates. The lobe serves to prevent transverse separation of the inner and outer link plates in use. This arrangement provides for rapid assembly and dismantling of the chain but may be unsuitable for certain applications since the recesses in the outer link plates may have the effect of reducing the overall strength of the chain.